Re: [Phys-l] Question about Quarks and the Standard Model

[Jack Uretsky <jlu@hep.anl.gov>]

	There is at least one misconception here.  See below.
On Wed, 15 Oct 2008, Tony wrote:

> It has been many decades since I've thought in detail about quarks. As a
> high school teacher it has not been part of our state requirements. With the
> LHC coming on line and beginning to make headlines, I thought I'd teach a
> little about quarks and the standard model of particles when I get to
> electromagnetism. I beginning to write my notes out as a handouts with some
> web animations for my students ...(and I'm sure I'm over preparing.)
> However, I've been doing a smattering of reading around the net and have a
> few questions that I can't settle on a clear answer, perhaps someone can
> help.
>
> Question 1 ..with parts
> Protons feel the electromagnetic force due to an exchange of gauge bosons,
> (the photon). Why is this exchange particle important? Is the particle a
> signal to one proton that a like charge is near? And do we know what the
> proton, or any particle, does in response to receiving an "exchange
> particle?"
	No, the coulomb force does not come from the "exchange of gauge 
bosons (the photon)".  Photons exert only transverse forces; the coulomb 
force is longitudinal.
	Why are photons important?  It depends on what questions you want 
to answer.  If you want to explain the photelectric effect, photons are 
crucial.  If you want to explain the cosmic microwave  background,  photons are 
immensely helpful.
	An excellent starting point for all such questions is  the Feynman 
Lectures.  Start with I-2-7, and go on from there.  I do NOT recommend the 
Wikipedia article, or any other discussion that speaks of ``wave-particle 
duality'' which, in my view, is a nonsense concept (for the benefit of the 
more advanced practitioner, Bardeen, among others taught us that the 
relevant dichotomy is coherence and incoherence).
	If I were teaching about photons, today, I would focus (sorry 
about that) on the role of photons in vision.  The rods and cones in the 
eye are remarkably sensitive photon detectors, playing, respectively, 
quite different roles.  I hope you get a chance to enjoy learning about 
this stuff.
				Regards,
					Jack


 >
> Question 2
> A couple of sites I ran across, e.g. http://arxiv.org/abs/astro-ph/0606093 ,
> mentioned "Quark Stars." Are there any other applications/explanations using
> quarks? I trying to come up with tangible reasons for studying quarks that
> go beyond their cool strangeness?  ;-)
>
> Question 3
> Finally, I've been reading various edu sites on the net about quarks and the
> standard model. Does anyone have a recommendation of a intro level book or
> article(s) that I could read for more information?
>
> Question 4
> In Your Humble Opinion, what Is the most important "thing" high school
> students should remember about quarks and/or the "standard model?"
>
> Thanks in advance,
> -Tony

--
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